Porous composite structures derived from multiphase polymer blends

Porous biopolymer structures have attracted a lot of attention in the recent years because of their potential applications in tissue engineering. In this work, porous structures of poly(lactic‐co‐glycolic acid) (PLGA) reinforced with organically modified montmorillonite (Cl15A) were fabricated. A ternary, co‐continuous blend consisting of PLGA/PS/Cl15A (PS: Polystyrene) was prepared by melt extrusion. Then, a porous PLGA composite was created by the sacrificial extraction of the PS phase. The morphological characterization revealed the creation of a well‐formed 3D porous network consisting of Cl15A‐reinforced PLGA. Quantitative results obtained from the scanning electron microscopy (SEM) micrographs of the fabricated porous structures show that small variations in the clay loading affect the geometrical characteristics (% porosity and pores average diameter) of these porous structures. The results suggest that these porous PLGA/clay structures may be promising candidates for mechanically strong scaffolds in tissue engineering applications, but this remains upon testing. POLYM. ENG. SCI., 55:1856–1863, 2015. © 2014 Society of Plastics Engineers     

Optimized compressive sampling for passive millimeter-wave imaging

In this paper, we briefly describe a single detector passive millimeter-wave imaging system, which has been previously presented. The system uses a cyclic sensing matrix to acquire incoherent measurements of the observed scene and then reconstructs the image using a Bayesian approach. The cyclic nature of the sensing matrix allows for the design of a single unified and compact mask that provides all the required random masks in a convenient way, such that no mechanical mask exchange is needed. Based on this setup, we primarily propose the optimal adaptive selection of sampling submasks out of the full cyclic mask to obtain improved reconstruction results. The reconstructed images show the feasibility of the imaging system as well as its improved performance through the proposed sampling scheme.     

Loss of viability of Listeria monocytogenes in contaminated processed cheese during storage at 4, 12 and 22 °C

The behaviour of Listeria monocytogenes in a processed cheese product was evaluated over time by inoculating the product with three different L. monocytogenes strains (Scott A, CA and a strain isolated from processed cheese) at three different inoculation levels (ca. 6 × 10⁵, ca. 6 × 10³ and 10² CFU/g of cheese or less) and after storage of the contaminated products at 4, 12 or 22 °C. Growth of L. monocytogenes was not observed in any of the experimental trials (experiments involving different combinations of strain, inoculum level and storage temperature) throughout the storage period. L. monocytogenes populations decreased over time with a rate that was strain- and storage temperature-dependent. Nonetheless, for cheeses that had been inoculated with the higher inoculum and stored at 4 °C viable populations of L. monocytogenes could be detected for up to nine months post-inoculation. The L. monocytogenes survival curves obtained from the different trials were characterised by a post-inoculation phase during which the populations remained essentially unchanged (lag phase) followed by a phase of logarithmic decline. The duration of the lag phase and the rate of inactivation of L. monocytogenes in the different trials were estimated based on data from the linear descending portions of the survival curves. In addition, a non-linear Weibull-type equation was fitted to the data from each survival curve with satisfactory results. The results of the present study emphasize that, according to the definition laid down in the European Union Regulation 1441/2007, the processed cheese product tested in this work should be considered and classified as one that does not support the growth of L. monocytogenes under reasonable foreseeable conditions of distribution and storage. However, post-processing contamination of the product should be austerely avoided as the pathogen can survive in the product for extended periods of time, particularly under refrigerated storage (4 °C).     

Effect of meat appearance on consumer preferences for pork chops in Greece and Cyprus

The effect of meat appearance on consumers’ preferences for pork chops was assessed using images manipulated for appearance characteristics. Data were collected from 412 consumers in Greece and Cyprus. Consumers were asked for their preference for pork chops from a book of computer-modified images and then completed a questionnaire of socio-demographic information, including eating and purchasing behaviour. Consumers under the age of 35 years showed preferences for dark red, lean pork, while consumers aged 35 years and older preferred either dark or light red pork. Gender appeared to be an important selection factor as men showed an increased preference for dark red pork while women preferred the light red. Consumers who stated that they like pork for its taste (91%) preferred either dark or light red pork chops while those who like pork for reasons other than taste preferred dark red, lean pork. Urban consumers preferred light red, fatty pork chops while the rural consumers preferred the dark red pork chops.     

Prevalence and concentration of Listeria monocytogenes in sliced ready-to-eat meat products in the Hellenic retail market

The aim of this work was to estimate the prevalence and concentration of Listeria monocytogenes in packaged precut (slices or cubes) ready-to-eat (RTE) meat products available in the Hellenic retail market. Samples of these RTE meat products (n = 209) were taken from local supermarkets during a 3-month period and analyzed for the presence of L. monocytogenes with an automated enzymatic qualitative immunoassay followed by biochemical confirmation of positive results. The concentration of the pathogen in the positive samples was also determined. Seventeen samples (8.1%) were positive for L. monocytogenes. Eight (47.1%) of these 17 samples were from the same manufacturer; 36.4% of the products tested from this manufacturer were positive for L. monocytogenes. When bacon samples were not considered, the estimated prevalence of L. monocytogenes in sliced RTE meat products was much lower (3.1%). The L. monocytogenes populations in all positive samples were low, < or = 10 CFU/g. In 64.7% of the L. monocytogenes-positive samples, other Listeria species, including L. innocua and L. welshimeri, were also present at <10 to 690 CFU/g. These results indicate that L. monocytogenes is present in low numbers but is in a considerable proportion of the packaged precut RTE meat products that are sold in the Hellenic retail market. Cooked ham and bacon cut in cubes were the sample types most often contaminated with L. monocytogenes. The higher level of handling (e.g., cutting) associated with these products may further increase the risk of contamination with L. monocytogenes.     

Simulation of intercritical annealing in low‐alloy TRIP steels

A coupled thermodynamic/kinetic calculation of austenite formation during intercritical annealing of low‐alloy TRIP steels is presented. The simulation was performed with the use of Dictra computational kinetics software, which employs a procedure for the numerical solution of the coupled diffusion equations involved, as well as mobility databases for the retrieval of the appropriate kinetic data. Calculated results are compared with available experimental data, in order to evaluate the model. Simulation results, regarding the amount and composition of austenite, the rate of transformation and the effect of annealing temperature and heating conditions, are presented and discussed. It is concluded that the simulation can assist the design of the intercritical annealing in these steels.     

An open financial services architecture based on the use of intelligent mobile devices

The scope of this paper is to explore, analyze and develop a universal architecture that supports mobile payments and mobile banking, taking into consideration the third and the emerging fourth generation communication technologies. Interaction and cooperation between payment and banking systems, integration of existing technologies and exploitation of intelligent procedures provide the prospect to develop an open financial services architecture (OFSA), which satisfies requirements of all involved entities. A unified scenario is designed and a prototype is implemented to demonstrate the feasibility of the proposed architecture.